[26] John Peckham was a Franciscan friar, and was nominated to the see of Canterbury by Nicholas III. in 1279. He had spent much time in the convent of his Order at Oxford, and there is a legend connecting him with a Johannes Juvenis or John of London, a youth who had attracted the attention and benevolence of Roger Bacon. This Johannes became one of the first mathematicians and opticians of the age, and was sent to Rome by Bacon, who entrusted to him the works which he was sending to Pope Clement IV. There is no reason for this view beyond the fact that both were called John, and distinguished in the same branches of learning. The _Perspectiva Communis_ was his principal work; it does not deal with perspective as now understood, but with elementary propositions of optics. It was first printed in Milan in or about 1482. [27] _De Vita Propria_, ch. x. p. 34. A remark in _De Sapientia_, Opera, tom. i. p. 578, suggests that Fazio began life as a physician: "Pater meus Facius Cardanus Medicus primo, inde Jurisconsultus factus est." CHAPTER II THE University of Pavia to which Jerome now betook himself was by tradition one of the learned foundations of Charlemagne.[28] It had certainly enjoyed a high reputation all through the Middle Ages, and had recently had the honour of numbering Laurentius Valla amongst its professors. In 1362, Galeazzo Visconti had obtained a charter for it from the Emperor Charles IV., and that it had become a place of consequence in 1400 is proved by the fact that, besides maintaining several professors in the Canon Law, it supported thirteen in Civil Law, five in Medicine, three in Philosophy, and one each in Astrology, Greek, and Eloquence. Like all the other Universities of Northern Italy, it suffered occasional eclipse or even extinction on account of the constant war and desolation which vexed these parts almost without intermission during the years following the formation of the League of Cambrai. Indeed, as recently as 1500, the famous library collected by Petrarch, and presented by Gian Galeazzo Visconti to the University, was carried off by the French.[29]